Method of spinning artificial silk



' Patented Oct. 30, 1928.

- UNITED STATES PATENT orrica.

HERMANN SCHMIDT, OF WIESDORF-ON-THE-BHINE, AND EMIL HUBERT, F ELBER- FELD, GERKANY, ASSIGNOIQS TO I. G. FARBENINDUSTBIE AKTIENGESELLSCHAFT, 0F FBANKFORT-ON-TEE-KAIN, GERMANY.

METHOD OF SPINNING ARTIFICIAL SILK.

1'0 Drawing. Application filed April 4, 1927, Serial No. 180,994, and in Germany June 11, 1926.

This invention relates to a new method of spinning artificial silk fromcuprammonium cellulose solutions and involves the use of an aqueous precipitating bath containing dis- 5 solved carbon dioxide or carbonic acid or its chemical equivalent, a soluble bicarbonand elasticity than silk produced by spin-.

ning into customary de-aerated bath and besides the use of a carbon dioxide containing as bath prevents,to a large extent, the deposition of copper salts upon the spinning nozzle. Dissolved carbon dioxide orjcarbonic acid and soluble bicarbonates have entirely similar effects, but the use of bicarbonates has the advantage that the carbon dioxide component is not expelled by raising the temperature of the recipitating bath, i. e., the bath may be'use at ordinary or somewhat elevated temperatures, if de- 5 sired, without loss of the efiective carbon dioxide. Any soluble bicarbonate such as the alkali metal and alkaline earth metal bicarbonates, e. g., sodium, bicarbonate or calcium' bicarbonate may be employed. It will 40 be understood the aqueous precipitating bath may contain carbon dioxide dissolved therein and chemically combined with water as thehypothetical acid H 00 or chemi-- cally com med with metals as bior acid carbonates as NaHCO The bicarbonate may be added to the bath as such, for ininstance, as sodium bicarbonate or formed in the bath by treating a solution of a metal hydroxide or carbonate with carbon dioxide. It will be further understood that in the vention threads is then effected according tp the cusfrom cuprammoniumcellulose appended claims where reference is made to dissolved carbon dioxide, carbonic acid and acid carbonates are embraced.

The following examples illustrate the in- Ewample 1.Cuprammonium cellulose solution is precipitated according to the stretch spinning process in as inning vessel of the customary type wit water at about 32 C.- containing approximately 10 to 20 mg. of free carbonic acid per liter. It is-likewise possible in this spinning process to employ water possessing slight hardness. The further treatment of the precipitated tomary methods.

Emmple 2.-Cuprammonium cellulose solution is precipitated. in water containing approximately 2 grams of sodium bicarbonate per liter'in a spinning vessel, for examleaccording to the process of German Pat.

v 0. 220,051. The further treatment of'the precipitated threads is effected according to the customary methods.

Claims: 1. Process for the manufacture of arti-' ficial' silk from a cuprammonium cellulose solution which. comprlses spinning the solution into an aqueous precipitating-bath containing dissolved carbon dioxide.

2. Process for the manufactureof artifi cial silk from a cuprammonium' cellulose 50- lution according to the stretch-spinning s method which comprises spinning the solution into an aqueous precipitating bath containing dissolved carbon dioxide.

- 3. Process for the manufacture of artificial silk which comprises spinning a cuprammonium cellulose solution into an aqueous precipitating bath containing a bicarbonate in solution.

4. Process for. the manufacture of artificial silk which comprises spimiing a cuprammonium cellulose solution into an aqueous precipitating bath containing a bicarbonate of an alkali iorming metal in solution.

In testimony whereof we have hereunto set ourhands.

-- HERMANN SCHMIDT.

HUBERT. 

